A known grille shutter apparatus configured to control a flow rate of air flowing from a grille opening portion into an engine room in accordance with opening and closing operations of a shutter mechanism provided at the grille opening portion arranged at a front portion of a vehicle body is disclosed, for example, in JPS58-139519U (hereinafter referred to as Patent reference 1). The known grille shutter apparatus disclosed in Patent reference 1 includes a shutter mechanism formed such that plural movable fins are aligned within a frame provided in an inside of the grille opening portion. A flow path of the air shaped at an inside of the frame may be opened and closed by rotating each of movable fins about a rotary shaft using a motor driving force.
For example, in a case where the vehicle is running at a high speed, an aerodynamic performance (for example, Cd value, that is, coefficient of drag) of the vehicle is enhanced by limiting an inflow of the air flowing into the inside of the engine room by establishing a closed state of the shutter mechanism. When an engine starts, warm-up time is shortened by reducing the flow rate of the air introduced into a radiator of the vehicle. When an engine temperature has increasing tendency, an open state of the shutter mechanism is established to increase the flow rate of the air flowing into the inside of the engine room so that the engine temperature is controlled at an appropriate temperature.
The known grille shutter apparatus disclosed in Patent reference 1 includes the shutter mechanism configured with a connecting member rotatably connected to one of opposing ends in a width direction of each of the movable fins. By forming a link mechanism using the connecting member, each of the movable fins is configured to rotate in conjunction with one another.
The configuration of the above-described grille shutter apparatus including the plural movable fins disclosed in Patent reference 1, however, may generate variations in an operational position (a rotation amount) of each of the movable fins due to, for example, a malfunction of bearing portions of the movable fins. Thus, in order to confirm whether the shutter mechanism operates normally, the operational position of each of the movable fins needs to be detected. However, the configuration of the grille shutter apparatus may be complicated because the number of a detection device, for example, a limit switch, is increased, or manufacturing cost may be increased.
A need thus exists for a grille shutter apparatus which is not susceptible to the drawback mentioned.